4x4 Not 4x4ing

[bluejeep]

So today i went out to plow the rest of my coustomers. The very first house and my 4x4 wont work! The light comes on but only rear tires spin. i sat and cranked the 4x4 lever for 10 min then i turned of the jeep and started it again. Backen into the snow and the 4x4 worked! This was going the day before it was in 4x4 and then come out of it by itself with the light still on and the lever still in the same place. Can anyone help me figure out whats going on, i really need it to work becouse a lot people will be really mad if i cant show up to plow.
Thanks

 

[jnjncj2]

What kind of rig is it (year, make, model)?

 

[OutOfStep]

betcha its a YJ

 

[Bounty__Hunter]

It's a vacuum disconnect problem for the front axle. The transfer case engages 4wd but the front axle won't work unless the vacuum disconnect on the pass. side axleshaft engages. Apparently it's moving enough to activate the 4wd light but not enough to lock the two axleshafts together.

Check the strength of the vacuum at the front axle, in each port. You'll have to have somebody shift from 2wd to 4wd and back to check both ports. They should be equally strong. You can then remove the vacuum disconnect (4 bolts) from the axle and ensure the shift fork moves freely. Use WD40 liberally in the disconnect to displace all water, water causes problems with the disconnect when the temp drops.

 

[bluejeep]

its 93 YJ 4.0L

 

[bluejeep]

It's a vacuum disconnect problem for the front axle. The transfer case engages 4wd but the front axle won't work unless the vacuum disconnect on the pass. side axleshaft engages. Apparently it's moving enough to activate the 4wd light but not enough to lock the two axleshafts together.

Check the strength of the vacuum at the front axle, in each port. You'll have to have somebody shift from 2wd to 4wd and back to check both ports. They should be equally strong. You can then remove the vacuum disconnect (4 bolts) from the axle and ensure the shift fork moves freely. Use WD40 liberally in the disconnect to displace all water, water causes problems with the disconnect when the temp drops.

That sounds like i need a lift. and i can only have a shop do that Where can should i look for the disconnect? i should also tell you that my trans is shot, it works but griends is some gears. Also maybe there is no fluid in the T case?
I think your right about the vacume, sometimes i get a violent jerk when the 4x4 should work but kinda cliks in and out....
Thanks for help!

 

[jnjncj2]

Yeah its more than likely the disconnect but if your running no oil in the T-case, you have or will have bigger fish to fry.

 

[MikeB]

Your best bet is to scrap the whole vaccuum system altogether, Its Unreliable and it always seems to screw up when you need it most. You can rig up a home made disconnect for the front axle for around 20-30 bucks
I'll post a link, it takes you through it step by step....pretty basic stuff.
http://home.earthlink.net/~stevenschreiber/cabledis.htm

 

[bluejeep]

Mike thanks, What kind of oil do i use in there?

 

[currupt4130]

or you can just lock the front axle into live position permanently by jamming the fork over to the locked side. do this by taking apart the vacuum motor and inserting a piece of rubber tube or something similar onto the vacuum shaft between the wall of the casing and the fork.

you use mercon dexcron 3 atf (dont quote me on the spelling, atf is short for automatic transmission fluid) most any brand of atf is mercon dexcron 3 rated, just make sure it is before buying it

 

[Bounty__Hunter]

Or by simply removing the vacuum disconnect and installing it upside down, this would lock the front axle together permanently. Works fine if you have an open diff, and a well balanced front driveshaft.

 

[bluejeep]

Will i be able to go into 4Lo then? And dosent it take more gas if your in 4x4 all the time?

 

[currupt4130]

having the front axle locked in doesnt put you 4x4, shifting your case does. yes you will still be able to go to 4 lo.

 

[bluejeep]

having the front axle locked in doesnt put you 4x4, shifting your case does. yes you will still be able to go to 4 lo.

sorry i dont know much about this 4x4 stuff. So what does locking do? Do i still do everything the same in terms of shifting?

 

[MikeB]

yeah,you still shift everything the same, when you lock your differentials both tires get equal amounts of power. for example, im sure at one time or another you've gotten stuck and have been totally frusterated because the tire that has absolutely no traction is spinning like crazy and the other isnt moving at all. Locking your differentials will eliminate that. But it all depends on how serious you are about wheeling, if you jeep is driven on the road 90% percent of the time it really wouldnt be worth it

 

[dingus]

you use ATF in the transfer case, gear oil in the differential.

 

[TwistedCU]

yeah,you still shift everything the same, when you lock your differentials both tires get equal amounts of power. for example, im sure at one time or another you've gotten stuck and have been totally frusterated because the tire that has absolutely no traction is spinning like crazy and the other isnt moving at all. Locking your differentials will eliminate that. But it all depends on how serious you are about wheeling, if you jeep is driven on the road 90% percent of the time it really wouldnt be worth it

You're describing locking the differential, while the mod described earlier was to lock the disconnect in the axle. He would still be running an open differential, but now his front driveshaft would be spinning while in 2WD and neither side would be spinning independant of the differential.

 

[currupt4130]

bluejeep, the yj uses a vacuum disconnect on the front axle. the front axle utilizes a two piece shaft which has a sliding collar to either lock them together or allow them to ride individual of each other. when they ride individual of each other they no long turn the front differential at all. this vacuum motor used to lock and unlock the axle collar is problematic and the problem is either in the vacuum lines goign to your motor or in the motor itself

this is the collar that shifts and locks the axles together, right now it is unlocked because the left half is not connected to the right

this is the collar locked switched to the live side

this is the vacuum motor that moves the collar between locked and unlocked (it is supposed to move to locked when you pull the lever on the tcase for 4x4)

this is the whole assembly on the axle (passenger side of the front axle)

 

[bluejeep]

OK, So if i turn the disconnect upside down. It will lock that slider in place and i will always have 4 wheels spinning, correct?

Now what’s the down side of this? I thought your not supposed to be driving in 4x4 on the freeway. I wont be able to make sharp turns, and will use more gas probably? Right?

 

[Junkpile]

OK, So if i turn the disconnect upside down. It will lock that slider in place and i will always have 4 wheels spinning, correct?

Now what’s the down side of this? I thought your not supposed to be driving in 4x4 on the freeway. I wont be able to make sharp turns, and will use more gas probably? Right?

No, it's a different thing. The wheels will be spinning the differential and Dshaft while driving. The front wheels still won't be driven though because the Tcase won't be locked in.